docs: def remove_annotation_value(graph, annotation, value):
      """Remove the given annotation/value pair to all qualified edges.
  
      :param pybel.BELGraph graph:
      :param str annotation:
      :param str value:
      """
      if annotation not in graph.defined_annotation_keywords:
          log.warning('annotation was not defined: %s', annotation)
          return
  
      for u, v, k in graph.edges(keys=True):
          if ANNOTATIONS not in graph[u][v][k]:
              continue
  
          if annotation not in graph[u][v][k][ANNOTATIONS]:
              continue
  
          if value not in graph[u][v][k][ANNOTATIONS][annotation]:
              continue
  
          del graph[u][v][k][ANNOTATIONS][annotation][value]